After all, the beef between the two still seems to be simmering and Swift has previously been emphatic about her opposition to streaming services. In 2014 she removed all her music from such outlets, saying, “Piracy, file sharing, and streaming have shrunk the numbers of paid album sales drastically.”

“It’s my opinion that music should not be free, and my prediction is that individual artists and their labels will someday decide what an album’s price point is,” she continued. “I hope they don’t underestimate themselves or undervalue their art.”

But today, as she celebrates 1989 selling over 10 million copies, her music again becomes available on streaming sites — which just might diminish Perry’s complete dominance of the streaming market today.

Perry talked about her long-running feud in an interview this week. When asked about her producer and collaborator Max Martin — with whom Swift wrote “Bad Blood” — (a song supposedly about Perry), she toldNME, “I can’t speak for him, but he didn’t know [who ‘Bad Blood’ was about]. I’m not supposed to tell him what he can and can’t do. I’m very fair; I’m super-duper fair and I’m not one of those people who’s like, ‘You can’t do that because I don’t like that person’. Just, like, you do you, make your own choices.”

She added: “I said that but, I mean, I’m not Buddha — things irritate me. I wish that I could turn the other cheek every single time, but I’m also not a pushover, you know? Especially when someone tries to assassinate my character with little girls [their respective fan groups]. That’s so messed up!”